Niche Packing and Local Coexistence in a Megadiverse Guild of Frugivorous Birds Are Mediated by Fruit Dependence and Shifts in Interaction Frequencies

D. Matthias Dehling, Giulio Valentino Dalla Riva, Matthew C. Hutchinson, Daniel B. Stouffer

Research output: Contribution to journalArticleResearchpeer-review

5 Citations (Scopus)

Abstract

Niche packing is one of the prevailing mechanisms underlying the increase in the number of co-occurring species and the extraordinary diversity of tropical ecosystems. However, it is not yet understood whether niche packing is facilitated by higher specialization and reduced niche overlap or, rather, by diffuse competition and increased niche overlap. We combined highly resolved bird-plant interaction networks, bird phylogenies, and plant functional traits to compare dietary niche overlap and foraging frequencies among frugivorous birds at seven sites in the tropical Andes. We quantified niche overlap on the basis of the traits of the plants used by each bird and related it to the degree of niche packing at the different sites. Niche complementarity decreased with increasing niche packing, suggesting that increasingly dense niche packing is facilitated by increased niche overlap. Pairwise niche overlap was mediated by shifts in foraging frequencies away from shared resources, and it decreased with decreasing phylogenetic relatedness and increasing dependence on fruit as resource. Our findings suggest that foraging choices are a key axis of diversification in frugivorous birds and that differences in resource use frequencies are already sufficient to reduce potential competition between ecologically similar species and facilitate niche packing, especially if species differ in their dependence on particular resources.

Original languageEnglish
Pages (from-to)855-868
Number of pages14
JournalThe American Naturalist
Volume199
Issue number6
DOIs
Publication statusPublished - Jun 2022
Externally publishedYes

Keywords

  • Eltonian foraging niche
  • Interspecific competition
  • Mutualism
  • Niche evolution
  • Niche overlap
  • Seed dispersal interaction networks

Cite this